OBJECTIVES: This study aims to discuss principles for economic evaluation and budget impact analysis of biosimilars.

METHODS: Via 14 in-depth interviews, experiences of Belgian stakeholders with reimbursement of biosimilars were evaluated and insight was gained into their views on the design of an economic evaluation and budget impact analysis for a biosimilar. These stakeholders included representatives of the HTA body, the medicines reimbursement agency, health insurance agencies, researchers, physicians, and pharmaceutical companies. A grounded theory approach was used to analyse the data.

RESULTS: No consensus was found on which technique of economic evaluation is deemed appropriate in the reimbursement decision of a biosimilar. The preference for a cost-minimization analysis was dependent on the view of the interviewee on potential differences between the originator and the biosimilar. Other interviewees suggested to perform a full cost-effectiveness analysis. When the reference product is not reimbursed, a full economic evaluation was considered appropriate. Not only for biologics or biosimilars, but for all medicines, frequent revisions on reimbursement decisions were advised. The interviewees seemed to agree that a budget impact analysis should be performed for the biosimilar. Ideally, the impact on the total healthcare budget is determined, however, differences outside the pharmaceutical budget might be limited. Evolutions in volume and price, and market entry of new products can be taken into account, but many uncertainties exist when making these assumptions.

CONCLUSIONS: Among stakeholders, no consensus exists on how to perform economic evaluation and budget impact analysis of biosimilars to support reimbursement decisions. Varying levels of knowledge and experience of stakeholders with biosimilars and health economics resulted in differing opinions.